git: openjdk/jdk: 8257079: ZGC: Fold ZMark::prepare_mark() into ZMark::start()

[Per Liden]

Changeset: f3fc0e08
Author:    Per Liden <pliden at openjdk.org>
Date:      2020-11-25 20:11:26 +0000
URL:       https://github.com/openjdk/jdk/commit/f3fc0e08

8257079: ZGC: Fold ZMark::prepare_mark() into ZMark::start()

Reviewed-by: stefank, ayang

! src/hotspot/share/gc/z/zMark.cpp
! src/hotspot/share/gc/z/zMark.hpp